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Department of Plant Pathology: Faculty Publications

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Articles 301 - 330 of 410

Full-Text Articles in Plant Biology

Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom. Iii. Dimethylsulfoniopropionate, Peter A. Lee, Jamie R. Rudisill, Aimee R. Neeley, Jennifer M. Maucher, David A. Hutchins, Yuanyuan Feng, Clinton E. Hare, Karine Leblanc, Julie M. Rose, Steven W. Wilhelm, Janet M. Rowe, Giacomo R. Ditullio Jan 2009

Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom. Iii. Dimethylsulfoniopropionate, Peter A. Lee, Jamie R. Rudisill, Aimee R. Neeley, Jennifer M. Maucher, David A. Hutchins, Yuanyuan Feng, Clinton E. Hare, Karine Leblanc, Julie M. Rose, Steven W. Wilhelm, Janet M. Rowe, Giacomo R. Ditullio

Department of Plant Pathology: Faculty Publications

The CLAW hypothesis argues that a negative feedback mechanism involving phytoplankton- derived dimethylsulfoniopropionate (DMSP) could mitigate increasing sea surface temperatures that result from global warming. DMSP is converted to the climatically active dimethylsulfide (DMS), which is transferred to the atmosphere and photochemically oxidized to sulfate aerosols, leading to increases in planetary albedo and cooling of the Earth’s atmosphere. A shipboard incubation experiment was conducted to investigate the effects of increased temperature and pCO2 on the algal community structure of the North Atlantic spring bloom and their subsequent impact on particulate and dissolved DMSP concentrations (DMSPp and DMSPd …

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Choline-Utilizing Microblal Strains For Biologically Controlling Fusarium Head Blight, David A. Schisler, Naseem I. Khan, Michael J. Boehm, Patricia J. Slininger Jan 2009

Choline-Utilizing Microblal Strains For Biologically Controlling Fusarium Head Blight, David A. Schisler, Naseem I. Khan, Michael J. Boehm, Patricia J. Slininger

Department of Plant Pathology: Faculty Publications

Three choline utilizing strains of microorganisms isolated from the anthers of wheat, Aureobasidium pullulans strainAS 55.2, Arthrobacter species strain OH 221.3, and Pseudomonas species strain AS 64.4, are superior antagonists of F. graminearum. These microorganisms are effective for suppression and control of FHB in cereals, particularly in wheat and barley.

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Dollar Spot Fungus Sclerotinla Homoeocarpa Produces Oxalic Acid, R. C. Venu, Robert A. Beaulieu, Terrance L. Graham, Ainhoa Martinez Medina, Michael J. Boehm Jan 2009

Dollar Spot Fungus Sclerotinla Homoeocarpa Produces Oxalic Acid, R. C. Venu, Robert A. Beaulieu, Terrance L. Graham, Ainhoa Martinez Medina, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa,. is one of the most devastating diseases of turfgrass worldwide. Many fungi belonging to the genus Sclerotinia produce oxalic acid along with pectolytic cell wall-degrading enzymes. A series of in vitro experiments showed the relationships among temperature, pH, mycelial growth and acid production. Mycelial growth and acid production were most abundant when S. homoeocarpa was grown between 20 and 30°C. Acid production by S. homoeocarpa appeared to be dependent upon the pH of the environment in which it was grown. High performance liquid chromatography analysis of spent broth revealed the presence of oxalic acid. …

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Molecular Characterization Of Citrus Tatter Leaf Virus Historically Associated With Meyer Lemon Trees: Complete Genome Sequence And Development Of Biologically Active In Vitro Transcripts, Satyanarayana Tatineni, Mohammad R. Afunian, Mark E. Hilf, Siddarame Gowda, William O. Dawson, Stephen M. Garnsey Jan 2009

Molecular Characterization Of Citrus Tatter Leaf Virus Historically Associated With Meyer Lemon Trees: Complete Genome Sequence And Development Of Biologically Active In Vitro Transcripts, Satyanarayana Tatineni, Mohammad R. Afunian, Mark E. Hilf, Siddarame Gowda, William O. Dawson, Stephen M. Garnsey

Department of Plant Pathology: Faculty Publications

Citrus tatter leaf virus isolated from Meyer lemon trees (CTLV-ML) from California and Florida induces bud union incompatibility of citrus trees grafted on the widely used trifoliate and trifoliate hybrid rootstocks. The complete genome sequence of CTLV-ML was determined to be 6,495 nucleotides (nts), with two overlapping open reading frames (ORFs) and a poly (A) tail at the 3′ end. The genome organization is similar to other capilloviruses, with ORF1 (nts 37 to 6,354) encoding a putative 242-kDa polyprotein which contains replication-associated domains plus a coat protein (CP), and ORF2 (nts 4,788 to 5,750), which is located within ORF1 in …

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Accumulation Of A 5′ Proximal Subgenomic Rna Of Citrus Tristeza Virus Is Correlated With Encapsidation By The Minor Coat Protein, Siddarame Gowda, Satyanarayana Tatineni, Svetlana Y. Folimonova, Mark E. Hilf, William O. Dawson Jan 2009

Accumulation Of A 5′ Proximal Subgenomic Rna Of Citrus Tristeza Virus Is Correlated With Encapsidation By The Minor Coat Protein, Siddarame Gowda, Satyanarayana Tatineni, Svetlana Y. Folimonova, Mark E. Hilf, William O. Dawson

Department of Plant Pathology: Faculty Publications

During replication, Citrus tristeza virus (CTV) produces large amounts of two unusual subgenomic (sg) RNAs that are positive-stranded and 5′ coterminal. Although these RNAs are produced in similar amounts and are similar in size, with LMT1 (~750 nt) only slightly larger than LMT2 (~650), we found that the similar sgRNAs are produced differently. We previously showed that the LMT1 RNA is produced by premature termination during genomic RNA synthesis. However, LMT2 production was found to correlate with virion assembly instead of RNA replication. The time course of accumulation of the LMT2 RNA occurred late, coinciding with virion accumulation. The long …

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Plant-Microbes Interactions In Enhanced Fertilizer-Use Efficiency, Anthony O. Adesemoye, Joseph W. Kloepper Jan 2009

Plant-Microbes Interactions In Enhanced Fertilizer-Use Efficiency, Anthony O. Adesemoye, Joseph W. Kloepper

Department of Plant Pathology: Faculty Publications

The continued use of chemical fertilizers and manures for enhanced soil fertility and crop productivity often results in unexpected harmful environmental effects, including leaching of nitrate into groundwater, surface runoff of phosphorus and nitrogen runoff, and eutrophication of aquatic ecosystems. Integrated nutrient management systems are needed to maintain agricultural productivity and protect the environment. Microbial inoculants are promising components of such management systems. This review is a critical summary of the efforts in using microbial inoculants, including plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi for increasing the use efficiency of fertilizers. Studies with microbial inoculants and nutrients have demonstrated that …

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Integrated Management Strategies For Phytophthora Sojae Combining Host Resistance And Seed Treatments, A. E. Dorrance, A. E. Robertson, S. Cianzo, L. J. Giesler, C. R. Grau, M. A. Draper, A. U. Tenuta, T. R. Anderson Dec 2008

Integrated Management Strategies For Phytophthora Sojae Combining Host Resistance And Seed Treatments, A. E. Dorrance, A. E. Robertson, S. Cianzo, L. J. Giesler, C. R. Grau, M. A. Draper, A. U. Tenuta, T. R. Anderson

Department of Plant Pathology: Faculty Publications

Phytophthora sojae has re-emerged as a serious soybean pathogen in the past decade. This may be due in part to changes in resistance levels in current cultivars, adoption of P. sojae populations to deployed Rps genes, and highly favorable environments in the past decade. This multilocation study evaluated the effect of seed treatments on the incidence and severity of Phytophthora root and stem rot on soybeans with different combinations of Rps genes and levels of partial resistance. The efficacy of the seed treatments was highly variable across locations. Seed treatments (metalaxyl and mefenoxam) provided protection and increased yields across cultivars …

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First Report Of Soybean Rust Caused By Phakopsora Pachyrhizi In Nebraska, S. R. Watson, L. J. Giesler, A. D. Ziems, T. E. Brovont Nov 2008

First Report Of Soybean Rust Caused By Phakopsora Pachyrhizi In Nebraska, S. R. Watson, L. J. Giesler, A. D. Ziems, T. E. Brovont

Department of Plant Pathology: Faculty Publications

Soybean rust caused by Phakopsora pachyrhizi Sydow was first observed in the continental United States in Louisiana in November 2004 (2). As part of the national soybean rust monitoring effort, samples were collected on 3 October 2007 during the scouting of fields with green leaves in southeastern Nebraska. After incubation at room temperature for 24 h, uredinea and urediniospores were observed with microscopic examination. Urediniospores were obovoid, hyaline to pale brown, and measured 20 to 30 × 18 to 20 μm.

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Enhanced Plant Nutrient Use Efficiency With Pgpr And Amf In An Integrated Nutrient Management System, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper Oct 2008

Enhanced Plant Nutrient Use Efficiency With Pgpr And Amf In An Integrated Nutrient Management System, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

A 3-year field study was conducted with field corn from 2005 to 2007 to test the hypothesis that microbial inoculants that increase plant growth and yield can enhance nutrient uptake, and thereby remove more nutrients—especially N, P, and K—from the field as part of an integrated nutrient management system. The field trial evaluated microbial inoculants, which include a commercially available plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhiza fungi (AMF), and their combination across 2 tillage systems (no-till and conventional till) and 2 fertilization regimes (poultry litter and ammonium nitrate). Data were collected on plant height, yield (dry mass of ears and …

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Method For Efficient Post Transcriptional Gene Slencing Using Intrinsic Direct Repeat Sequences And Utilization Thereof Infunctional Genomics, Amitava Mitra, Chonglie Ma Jun 2008

Method For Efficient Post Transcriptional Gene Slencing Using Intrinsic Direct Repeat Sequences And Utilization Thereof Infunctional Genomics, Amitava Mitra, Chonglie Ma

Department of Plant Pathology: Faculty Publications

It is well documented that transgenes with inverted repeats can efficiently trigger post-transcriptional gene silencing (PTGS), presumably via a double stranded RNA induced by complementary sequences in their transcripts. We show here that transgenes with intrinsic direct repeats can also induce PTGS at a very high frequency (80-100%). A transgene with three or four repeats induced PTGS in almost 100% of the primary transformants, regardless of whether a strong (en hanced 35S promoter) or a relatively weak (chlorophyll a?b binding protein promoter) promoter was used. The PTGS induced by three or four repeats is consistently inherited in Subsequent generations, and …

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An Antibiotic Complex From Lysobacter Enzymogenes Strain C3: Antimicrobial Activity And Role In Plant Disease Control, S. Li, C. C. Jochum, F. Yu, K. Zaleta-Rivera, L. Du, Steven D. Harris, Gary Y. Yuen Jun 2008

An Antibiotic Complex From Lysobacter Enzymogenes Strain C3: Antimicrobial Activity And Role In Plant Disease Control, S. Li, C. C. Jochum, F. Yu, K. Zaleta-Rivera, L. Du, Steven D. Harris, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at …

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Uses Of The Pseudomonas Syringae Effector Protein Hopu1 Related To Itsability To Adp-Rbosylate Eukaryotc Rna Binding Protens, James R. Alfano, Zheng Qing Fu, Thomas E. Elthon Jan 2008

Uses Of The Pseudomonas Syringae Effector Protein Hopu1 Related To Itsability To Adp-Rbosylate Eukaryotc Rna Binding Protens, James R. Alfano, Zheng Qing Fu, Thomas E. Elthon

Department of Plant Pathology: Faculty Publications

The bacterial plant pathogen Pseudomonas Syringae injects effector proteins into host cells via a type III protein secre tion system to cause disease. The invention relates to the discovery that the type III effector HopU1 is a mono-ADP ribosyltransferase (ADP-RT) and suppresses plant innate immunity. The HopU1 substrates in Arabidopsis thaliana extracts were RNA-binding proteins that possess RNA recognition motifs (RRMs). A. thaliana knock-out lines defective in the glycine-rich RNA-binding protein AtGRP7, a HopU1 substrate, were more susceptible than wild type plants to P syringae. The ADP-ribosylation of AtGRP7 by HopU1 required two arginines within the RRM. The inven tion …

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Comparison Of Plant Growth-Promotion With Pseudomonas Aeruginosa And Bacillus Subtilis In Three Vegetables, A. O. Adesemoye, M. Obini, E. O. Ugoji Jan 2008

Comparison Of Plant Growth-Promotion With Pseudomonas Aeruginosa And Bacillus Subtilis In Three Vegetables, A. O. Adesemoye, M. Obini, E. O. Ugoji

Department of Plant Pathology: Faculty Publications

Our objective was to compare some plant growth-promoting rhizobacteria (PGPR) properties of Bacillus subtilis and Pseudomonas aeruginosa as representatives of their two genera. Solanum lycopersicum L. (tomato), Abelmoschus esculentus (okra), and Amaranthus sp. (African spinach) were inoculated with the bacterial cultures. At 60 days after planting, dry biomass for plants treated with B. subtilis and P. aeruginosa increased 31% for tomato, 36% and 29% for okra, and 83% and 40% for African spinach respectively over the non-bacterized control. Considering all the parameters tested, there were similarities but no significant difference at P < 0.05 between the overall performances of the two organisms.

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In Planta Distribution Of ‘Candidatus Liberibacter Asiaticus’ As Revealed By Polymerase Chain Reaction (Pcr) And Real-Time Pcr, Satyanarayana Tatineni, Uma Shankar Sagaram, Siddarame Gowda, Cecile J. Robertson, William O. Dawson, Toru Iwanami, Nian Wang Jan 2008

In Planta Distribution Of ‘Candidatus Liberibacter Asiaticus’ As Revealed By Polymerase Chain Reaction (Pcr) And Real-Time Pcr, Satyanarayana Tatineni, Uma Shankar Sagaram, Siddarame Gowda, Cecile J. Robertson, William O. Dawson, Toru Iwanami, Nian Wang

Department of Plant Pathology: Faculty Publications

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic α- proteobacterium that is yet to be cultured. In this study, a combination of traditional polymerase chain reaction (PCR) and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence of ‘Candidatus Liberibacter asiaticus,’ respectively, were used to examine the distribution and movement of the HLB pathogen in the infected citrus tree. We found that ‘Ca. Liberibacter asiaticus’ was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and …

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Three Genes Of Citrus Tristeza Virus Are Dispensable For Infection And Movement Throughout Some Varieties Of Citrus Trees, Satyanarayana Tatineni, Cecile J. Robertson, Stephen M. Garnsey, Moshe Bar-Joseph, Siddarame Gowda, William O. Dawson Jan 2008

Three Genes Of Citrus Tristeza Virus Are Dispensable For Infection And Movement Throughout Some Varieties Of Citrus Trees, Satyanarayana Tatineni, Cecile J. Robertson, Stephen M. Garnsey, Moshe Bar-Joseph, Siddarame Gowda, William O. Dawson

Department of Plant Pathology: Faculty Publications

Citrus tristeza virus (CTV), a member of the Closteroviridae, possesses a 19.3-kb positive-stranded RNA genome that is organized into twelve open reading frames (ORFs). The CTV genome contains two sets of conserved genes, which are characteristic of this virus group, the replication gene block (ORF 1a and 1b) and the quintuple gene block (p6, HSP70 h, p61, CPm, and CP). With the exception of the p6 gene, they are required for replication and virion assembly. CTV contains five additional genes, p33, p18, p13, p20 and p23, in the 3′ half of the genome, some of which (p33, p18 and …

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Regulation Of Apical Dominance In Aspergillus Nidulans Hyphae By Reactive Oxygen Species, Camile P. Semighini, Steven D. Harris Jan 2008

Regulation Of Apical Dominance In Aspergillus Nidulans Hyphae By Reactive Oxygen Species, Camile P. Semighini, Steven D. Harris

Department of Plant Pathology: Faculty Publications

In fungal hyphae, apical dominance refers to the suppression of secondary polarity axes in the general vicinity of a growing hyphal tip. The mechanisms underlying apical dominance remain largely undefined, although calcium signaling may play a role. Here, we describe the localized accumulation of reactive oxygen species (ROS) in the apical region of Aspergillus nidulans hyphae. Our analysis of atmA (ATM) and prpA (PARP) mutants reveals a correlation between localized production of ROS and enforcement of apical dominance. We also provide evidence that NADPH oxidase (Nox) or related flavoproteins are responsible for the generation of ROS at hyphal tips and …

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An Immunofluorescence Assay To Detect Urediniospores Of Phakopsora Pachyrhizi, Fulya Baysal-Gurel, Melanie L. Lewis Ivey, Anne E. Dorrance, Douglas Luster, Reid Frederick, Jill Czarnecki, Michael J. Boehm, Sally A. Miller Jan 2008

An Immunofluorescence Assay To Detect Urediniospores Of Phakopsora Pachyrhizi, Fulya Baysal-Gurel, Melanie L. Lewis Ivey, Anne E. Dorrance, Douglas Luster, Reid Frederick, Jill Czarnecki, Michael J. Boehm, Sally A. Miller

Department of Plant Pathology: Faculty Publications

An indirect immunofluorescence spore assay (IFSA) was developed to detect urediniospores of Phakopsora pachyrhizi, utilizing rabbit polyclonal antisera produced in response to intact nongerminated (SBR1A) or germinated (SBR2) urediniospores of P. pachyrhizi. Both antisera were specific to Phakopsora spp. and did not react with other common soybean pathogens or healthy soybean leaf tissue in enzyme-linked immunosorbent assay (ELISA). SBR1A and SBR2 bound to P. pachyrhizi and P. meibomiae urediniospores were detected with goat anti-rabbit Alexa Fluor 488-tagged antiserum using a Leica DM IRB epifluorescent microscope with an I3 blue filter (excitation 450 to 490 nm, emission 515 nm). The …

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Virulence Diversity Of The Common Bean Rust Pathogen Within And Among Individual Bean Fields And Development Of Sampling Strategies, C. Jochua, M. I. V. Amane, J. R. Steadman, X. Xue, K. M. Eskidge Jan 2008

Virulence Diversity Of The Common Bean Rust Pathogen Within And Among Individual Bean Fields And Development Of Sampling Strategies, C. Jochua, M. I. V. Amane, J. R. Steadman, X. Xue, K. M. Eskidge

Department of Plant Pathology: Faculty Publications

There is a dearth of information on pathogen variation within an individual field. In this study, virulence diversity of Uromyces appendiculatus, cause of bean rust, within individual fields was investigated. From six bean fields in the United States, Honduras, Dominican Republic, and South Africa, 380 U. appendiculatus isolates were differentiated into 65 virulence phenotypes on bean lines containing Andean- and Middle American-derived rust resistance genes. Race variation among bean rust isolates from different geographic regions was found, and virulence phenotypes found in fields from tropical and subtropical regions were more virulent and diverse than those found in fields from …

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Branching Of Fungal Hyphae: Regulation, Mechanisms And Comparison With Other Branching Systems, Steven D. Harris Jan 2008

Branching Of Fungal Hyphae: Regulation, Mechanisms And Comparison With Other Branching Systems, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of rapidly growing hyphae to generate new polarity axes that result in the formation of a branch represents one of the most important yet least understood aspects of fungal cell biology. Branching is central to the development of mycelial colonies and also appears to play a key role in fungal interactions with other organisms. This review presents a description of the two major patterns of hyphal branching, apical and lateral, and highlights the roles of internal and external factors in the induction of branch formation. In addition, potential mechanisms underlying branch site selection are outlined, and the possible …

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First Report Of Annual Bluegrass Weevil, Listronotus Maculicollis, Damage In Ohio, John L. Koenig, David J. Shetlar, Joseph W. Rimelspach, Michael J. Boehm Jan 2008

First Report Of Annual Bluegrass Weevil, Listronotus Maculicollis, Damage In Ohio, John L. Koenig, David J. Shetlar, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Annual bluegrass weevil [Listronotus maculicollis (Kirby) (1)] larvae, pupae, and adults were recovered and identified in a sample received by the C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC) at Ohio State University on 19 June 2007. Damage to the approaches and collars of four golf course putting greens was detected by the superintendent of Stonewater Golf Club, Highland Heights, OH (a suburb of Cleveland) during the week of 11 June 2007. The superintendent suspected damage from the larvae of the black turfgrass ataenius, Ataenius spretulus (1). Insecticide applications applied to suppress black turfgrass ataenius did not provide …

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Rapid Development Of Fungicide Resistance By Sclerotinia Homoeocarpa On Turfgrass, Young-Ki Jo, Seog Won Chang, Michael J. Boehm, Geunhwa Jung Jan 2008

Rapid Development Of Fungicide Resistance By Sclerotinia Homoeocarpa On Turfgrass, Young-Ki Jo, Seog Won Chang, Michael J. Boehm, Geunhwa Jung

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups were found in S. homoeocarpa field populations on both fairway and putting green turfgrass at a research field …

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Inoculation Strategies To Assess Biological Interactions Between Fusarium And Alternaria Species Infecting Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen Jan 2008

Inoculation Strategies To Assess Biological Interactions Between Fusarium And Alternaria Species Infecting Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

New cultivars of sorghum are being developed for increased food use, as livestock feed, and for the bioenergy industry by manipulation of secondary metabolic pathways through breeding. Previous work has suggested that such modifications may have an impact on cultivar response to fungal pathogens. We investigated four inoculation strategies that may be used in studies involving pathogens of sorghum. Plants of elite sorghum genotypes ‘Wheatland’ and RTx430, commonly used in breeding programs, were inoculated with isolates of Alternaria alternata, Fusarium equiseti, Fusarium proliferatum, Fusarium solani, Fusarium thapsinum, and Fusarium verticillioides recovered from field-grown sorghum. Wound inoculation of the peduncles …

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Wheat Streak Mosaic Virus Lacking Helper Component-Proteinase Is Competent To Produce Disease Synergism In Double Infections With Maize Chlorotic Mottle Virus, Drake C. Stenger, Brock A. Young, Feng Qu, Thomas Jack Morris, Roy French Oct 2007

Wheat Streak Mosaic Virus Lacking Helper Component-Proteinase Is Competent To Produce Disease Synergism In Double Infections With Maize Chlorotic Mottle Virus, Drake C. Stenger, Brock A. Young, Feng Qu, Thomas Jack Morris, Roy French

Department of Plant Pathology: Faculty Publications

The tritimovirus Wheat streak mosaic virus (WSMV) and the machlomovirus Maize chlorotic mottle virus (MCMV) each cause systemic chlorosis in infected maize plants. Infection of maize with both viruses produces corn lethal necrosis disease (CLND). Here, we report that complete deletion of the WSMV helper component-proteinase (HC-Pro) coding region had no effect on induction of CLND symptoms following coinoculation of maize with WSMV and MCMV. We further demonstrated that elevation of virus titers in double infections, relative to single infections, also was independent of WSMV HC-Pro. Thus, unlike potyvirus HC-Pro, WSMV HC-Pro was dispensable for disease synergism. Because disease synergism …

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Pseudomonas Avr And Hop Proteins, Their Encoding Nucleic Acids, And Use Thereof, James R. Alfano, Alan Collmer, Samuel W. Cartinhour, David J. Schneider May 2007

Pseudomonas Avr And Hop Proteins, Their Encoding Nucleic Acids, And Use Thereof, James R. Alfano, Alan Collmer, Samuel W. Cartinhour, David J. Schneider

Department of Plant Pathology: Faculty Publications

One aspect of the present invention relates to isolated nucleic acid molecules encoding avirulence proteins or polypeptides of Pseudomonas syringae pv. syringae DC 3000, or nucleic acid moleculues which are complementary thereto. Expression vectors, host cells, and transgenic plants which include the DNA molecules of the present invention are also disclosed. Another aspect relates to the isolated proteins or polypeptides and compositions containing the same. The various nucleic acid molecules and proteins of the present invention can be used to impart disease resistance to a plant, make a plant hypersusceptible to colonization by nonpathogenic bacteria, modify a metabolic pathway in …

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Association Of Ergot Alkaloids With Conidiation In Aspergillus Fumigatus, Christine M. Coyle, Shawn C. Kenaley, William R. Rittenour, Daniel G. Panaccione Jan 2007

Association Of Ergot Alkaloids With Conidiation In Aspergillus Fumigatus, Christine M. Coyle, Shawn C. Kenaley, William R. Rittenour, Daniel G. Panaccione

Department of Plant Pathology: Faculty Publications

Ergot alkaloids are mycotoxins that affect the nervous and reproductive systems of exposed individuals through interactions with monoamine receptors. They have been studied more widely in ergot fungi and grass endophytes but also are found in Aspergillus fumigatus, an opportunistic human pathogen that reproduces and disseminates exclusively through conidia. The ergot alkaloids festuclavine and fumigaclavines A, B and C are present in or on conidia of A. fumigatus. Cultures of the fungus that are free of conidia are difficult to obtain, obscuring comparisons of conidia versus vegetative hyphae as sources of the ergot alkaloids. To create conidiation-deficient strains of A. …

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Regulation Of Hyphal Morphogenesis By Cdc42 And Rac1 Homologues In Aspergillus Nidulans, Aleksandra Virag, Maurice P. Lee, Haoyu Si, Steven D. Harris Jan 2007

Regulation Of Hyphal Morphogenesis By Cdc42 And Rac1 Homologues In Aspergillus Nidulans, Aleksandra Virag, Maurice P. Lee, Haoyu Si, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of filamentous fungi to form hyphae requires the establishment and maintenance of a stable polarity axis. Based on studies in yeasts and animals, the GTPases Cdc42 and Rac1 are presumed to play a central role in organizing the morphogenetic machinery to enable axis formation and stabilization. Here, we report that Cdc42 (ModA) and Rac1 (RacA) share an overlapping function required for polarity establishment in Aspergillus nidulans. Nevertheless, Cdc42 appears to have a more important role in hyphal morphogenesis in that it alone is required for the timely formation of lateral branches. In addition, we provide genetic evidence …

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Response Of Soybean Cultivars To Bean Pod Mottle Virus Infection, Amy D. Ziems, Loren J. Giesler, George L. Graef, Margaret G. Redinbaugh, Jean L. Vacha, Sueann Berry, Laurence V. Madden, Anne E. Dorrance Jan 2007

Response Of Soybean Cultivars To Bean Pod Mottle Virus Infection, Amy D. Ziems, Loren J. Giesler, George L. Graef, Margaret G. Redinbaugh, Jean L. Vacha, Sueann Berry, Laurence V. Madden, Anne E. Dorrance

Department of Plant Pathology: Faculty Publications

Bean pod mottle virus (BPMV) has become increasingly common in soybean throughout the north-central region of the United States. Yield loss assessments on southern soybean germplasm have reported reductions ranging from 3 to 52%. Currently, no soybean cultivars have been identified with resistance to BPMV. The objective of this study was to determine the impact of BPMV infection on soybean cultivars representing a broad range of northern soybean germplasm by comparing inoculated and noninoculated soybean plants in paired row studies. In all, 30 and 24 cultivars were evaluated in Nebraska (NE) in which soybean plants were inoculated at the V3 …

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Basa Regulates Cell Wall Organization And Asexual/Sexual Sporulation Ratio In Aspergillus Nidulans, Shaojie Li, Dapeng Bao, Gary Yuen, Steven D. Harris, Ana M. Calvo Jan 2007

Basa Regulates Cell Wall Organization And Asexual/Sexual Sporulation Ratio In Aspergillus Nidulans, Shaojie Li, Dapeng Bao, Gary Yuen, Steven D. Harris, Ana M. Calvo

Department of Plant Pathology: Faculty Publications

Sphingolipid C4 hydroxylase catalyzes the conversion of dihydrosphingosine to phytosphingosine. In Saccharomyces cerevisiae, Sur2 is essential for sphingolipid C4 hydroxylation activity but not essential for normal growth. Here we demonstrate that the Aspergillus nidulans Sur2 homolog BasA is also required for phytosphingosine biosynthesis but is also essential for viability. We previously reported that a point missense mutation in basA resulted in aberrant cell wall thickening. Here our data suggest that accumulation of dihydrosphingosine is responsible for this phenotype. In addition, two different mutations in basA consistently accelerated the transition from asexual development to sexual development compared to the wild-type …

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Free-Living Dorylaimid Nematodes From Nature Reserves In Costa Rica. The Genus Pachydorylaimus Siddiqi, 1983, A. Esquivel, P. Guerrero, R. Peña-Santiago, Thomas O. Powers Jan 2007

Free-Living Dorylaimid Nematodes From Nature Reserves In Costa Rica. The Genus Pachydorylaimus Siddiqi, 1983, A. Esquivel, P. Guerrero, R. Peña-Santiago, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

A taxonomic study of three species, two known and one new, belonging to the genus Pachydorylaimus Siddiqi, 1983 from natural areas in Costa Rica is presented. Pachydorylaimus holovachovi sp. n. is described and can be distinguished by its body 0.90-1.00 mm long, lip region 14-17 μm wide, odontostyle 13-15 μm long, odontophore morphology with differentiated hyaline spindle-shaped area surrounding its junction to pharyngeal lining but lacking distinct basal flanges, total stylet length 35- 44 μm, pars refringens vaginae absent, V = 43-47, female tail straight and tapering to an acute tip (57- 78 μm, c = 12.5-15.8, c’ = 2.0-3.0), …

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Genetic Diversity In Populations Of Xanthomonas Campestris Pv. Campestris In Cruciferous Weeds In Central Coastal California, A. Ignatov, A. Sechler, E. L. Schuenzel, I. Agarkova, B. Oliver, A. K. Vidaver, N. W. Schaad Jan 2007

Genetic Diversity In Populations Of Xanthomonas Campestris Pv. Campestris In Cruciferous Weeds In Central Coastal California, A. Ignatov, A. Sechler, E. L. Schuenzel, I. Agarkova, B. Oliver, A. K. Vidaver, N. W. Schaad

Department of Plant Pathology: Faculty Publications

Xanthomonas campestris pv. campestris (X. campestris) infects a large number of cruciferous plants, including weeds. California has one of the largest and most diverse populations of wild cruciferous plants in the world. Although considerable information is available on the genetic diversity of X. campestris in commercial crop plants, nothing is known about the diversity in strains infecting weeds. To assess the genetic diversity among strains of X. campestris in weeds in noncultivated and cultivated areas, strains of the pathogen were isolated from populations of cruciferous weeds growing in coastal valley crop-production sites and from remote nonproduction sites along the …

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